Generally, plasma is a fourth state of materials, which is neither solid, nor liquid, nor gas. The plasma is formed of partially ionized gas. The plasma is electrically neutral, but has electric conductivity by positively, or negatively ionized particles. Also, the plasma has sensitivity to electromagnetic field. The plasma may be controlled artificially by controlling the electromagnetic field applied to the plasma. Therefore, the plasma may be used in manufacturing a semiconductor element, a flat panel display, or other intergrated circuits.
That is, during a process of thin lay deposition or pattern etching, a high frequency electric power such as radio frequency (RF) is applied to both electrodes of a chamber. Then, reaction gas is supplied into the chamber in order to generate a glow discharge, thereby etching a substrate or depositing a thin layer on a surface of a wafer.
Recently, a variety of plasma reactors that can perform a substrate treatment using the plasma have been developed.
According to a shape of an antenna and a dielectric window, the plasma reactors are classified into a solenoid type, a planar type, or a dome type.
A conventional solenoid type plasma reactor generates a plasma reaction by disposing a solenoid coil around the dielectric window.
However, since the conventional solenoid type plasma reactor has a relatively high inductance, a sputtering problem due to high voltage occurs and the heat generation efficiency is lowered.
The planar type plasma reactor is disclosed in U.S. Pat. No. 4,948,458 to Lam antenna disposed above the dielectric window.
However, the planar type plasma reactor has a short distance between a plasma source and the wafer, thereby making it difficult to have independent control of ion energy reaching the surface of the wafer.
The dome type plasma reactor is disclosed in U.S. Pat. No. 6,475,335 to Applied Materials.
The dome type plasma reactor has a dome shape dielectric window protruding upward. The antenna is disposed around the dome, and a gas is supplied from the side of the dome.
However, the dome type plasma reactor has a difficulty in providing a uniform etching rate in the case where the substrate is large-sized substrate.